The primary goal of this proposal is to develop a short-term culture of mature mouse cochlea. This is a new area of interest for the investigator in that the major model in the laboratory at present is the turtle auditory papilla. The development of this procedure will open avenues to the investigation of transgenic animals as well as allow for molecular manipulations of the tissue in the short term to investigate the physiology of hearing at the molecular level. The usefulness of this preparation is multifaceted. It can be used to explore mechanical, electrophysiological and synaptic properties of both sensory and nonsensory cells. By establishing a culture system that survives for several days gene expression studies using viral transfections or gene gun technology can be incorporated into physiological studies. In addition, the time course of processes leading to ototoxicity, either pharmacological or environmental (i.e. noise exposure) can also be investigated. Additionally, working with mouse cultures will allow for knockout/knockin mice to be investigated. This proposal attempts to lay the groundwork for these types of investigations by studying the mechanical and electrophysiological properties of mouse sensory hair cells maintained in an organotypic culture for up to four days. The specific aims are first to determine the most mature age that the organ of corti can be dissected from the mouse inner ear and viable electrophysiological recordings obtained at 35 degrees Celsius. Secondly, tissue from the age determined in specific aim 1 will be placed into culture for up to four days. Basic electrophysiological measurements including the complement of basolateral conductances and mechano- electric-transducer currents will be measured from cells at specific positions along the cochlea over time of culture to optimize conditions that maintain viability but do not promote differentiation of cell properties. This work qualifies as a feasibility study because mature mouse cochlea have not been successfully cultured, nor have electrophysiological measurements been made at physiological temperatures. Although several obstacles exist, if overcome, this preparation has great potential for exploring both the physiological and pathophysiological processing in the inner ear.